Process of making a mat or felted structure



March 4, 1958 J: STEPHENS 2,825,339

PROCESS OF MAKING A VAT OR FELTED STRUCTURE Oyigingl Filed Nov. 25, 1949INVENTOR. dose 0h E fifepfie/za I ATTOR EX United States Patent 6 FPROCESS OF MAKING A MAT R FELTED STRUCTURE Joseph F. Stephens, KansasCity, Mo., assignor to Gustin- Bacon Manufacturing Company, acorporation of Missouri Original application November 23, 1949, SerialNo. 129,167, now Patent No. 2,595,855, dated November 30, 1954. Dividedand this application May 21, 1954, Serial No. 431,669

10 (Ilaims. (Cl. 154-28) This invention relates to an improvement inacoustical and heat insulating bonded mats or felts used as thermal oracoustical insulating material and the method of making same, and refersmore particularly to a felted fibrous structure into which isincorporated a rubberlike elastic material in combination with athermoplastic or thermosetting resinous material. The fibers and theelasticmaterial are bonded together by the resinous material, and themat or felt is manufactured in a continuous. operation by depositing thefibers, elastic material, and binder upon a conveyor where a mat isformed by flowing and hardening or curing the resinous binder materialthrough the application of heat.

The present application is a division of my copending application SerialNo. 129,167, filed November'23, 1949, now Patent No. 2,695,855, issuedNovember 30, 1954.

A mat having the structure contemplated has improved characteristicsover material now employed for the purpose, is economical tomanufacture, has extensive usesas thermal or acoustical insulation andas padding or upholstering material. For example, in the modernautomobile it may be used in the dash panel for the purpose ofinsulating against both the heat and sound of the engine; it may be usedas a sound and heat insulation under the rubber floor mats, as a topliner for sound absorption, for lining air intake ducts, and in thefabrication of shroud sides.

An object of the invention is to provide a mat structure which isefiective as a heat and sound insulating material which possessesunusual properties of resilience and which has a high degree ofintegrity or strength.

Another object is to provide a mat in which are incorporated carrier andfiller fibers of organic or inorganic nature or a mixture of the two incombination with an elastic material and bonded with a thermoplastic orthermosetting resin into a resilient padv which is easily shaped andsufi'lciently flexible to fit irregular surfaces.

A further object is to provide a felted structurewhich is economical tomanufacture and effective in meeting the requirements for which it isutilized.

In the accompanying drawing, the single figure represents sc hematicallythe method embodying the present invention.

In the manufacture of this materialfrom organic or inorganicfibers or acombination of the two, the fibers or filaments are first prepared bychopping or cutting to the desired length, if they are not of the properlength as-supplied. Selected quantities and types of fibers are theappropriatelyblended, the blend consisting in some part of longerlengthcarrier fibers and in greater part of: shorter length filler fibers.

The reason for using carrier fibers and fillerfibers in the;blendzisthat in;order:to make use of ..theetcheaper filler fibers, itis: necessary to-blend therewith a sufficient 2,825,389 Patented Mar. 4,1958 percentage of the longer carrier fiber to have the blend or mixturesuccessfully carry through textile equipment such as garnetts. If allshort filler fibers or too high a percentage thereof are utilized, theresult is the loss of an objectionable amount in the form of droppingsin the garnett operation. These longer carrier fibers are also used toimpart strength to the finished product.

The blend 9 of carrier and filler fibers is fed to the hopper 16 of ahopper type garnett feeder, then processed through the garnett 11, fromthe final cylinder 12 of which it is stripped ofl? by a dofi'er roll 13.The dotler roll is in turn stripped of the fibers by a brush roll '14,which is in turn stripped by a beater or wind roll 15 or by air airstream which propels the fibers forward from the garnett. A suitableform of apparatus for doing this is disclosed in Hubert O. Sheidleyapplication Serial No. 210,544, filed February 12, 1951 now Patent No.2,619,151, issued November 25, 1952.

The fibers are carried by the air stream into a hood or settling chamber16, which is open on the side from which the fibers are fed and closedon all other sides except the bottom which is comprised of a foraminousconveyor belt 17 positioned over a vacuum box 18. 'A partial vacuum ispulled through the foraminous belt causing the fibers to be attracted toand to lay up on the upper face of the foraminous belt in the form of amat or felt as the belt moves through the hood. The vacuurn also servesto exhaust the air which transports the fiber into the hood. Suctionfrom the foraminous belt builds up the fibers in the form of a feltedmat 19 on the surface of the moving belt conveyor. This arrangement alsois shown in the aforementioned Sheidley application.

According to the present invention, in the vicinity of the garnettstripping mechanism (which comprises the brush and beater rollspreviously mentioned) and between the garnett and the foraminous belt, apowdered thermosetting or thermoplastic resin is introduced by feedingthe resin into a separate air stream as at 20 and merging such airstream with the air stream which is transporting the fibers. With suchpowdered thermosetting or thermoplastic resin, there is mixed adesirable proportion of powdered rubber, either in the vulcanized orunvulcanized state, so that there is airborne into the hood or settlingchamber-and deposited on the foraminous belt, a combination of fibers,powdered resin, and powdered elastic material, the powdered materialbeing intimately interspersed throughout the felted web.

Instead of airborne powder resin, a wet spray may be used in which theresin is in the form of either a solution or dispersion and to whichrubber has been added in the form of a rubber latex or solution. In suchuse the wet resin and rubber is sprayed into the air stream carrying thefibers, thus coating and intimately comingling with the fibers prior totheir deposition and accumulation on the conveyor belt.

It is also contemplated that the rubber may be added in the form of arubber latex or solution'to the fiber and dried on the surface of thefiber before such fiber is fed to the garnett. In such case only thethermosetting or thermoplastic resin is introduced in dry orwet statebetween the garnett and'the foraminous belt upon which the mat isformed.

In place of incorporating powdered rubber or of pretreating the fiberwith rubber, fiber or fiber threads which contain such rubber on thesurface or interspersed throughout the mass in small discrete particlesor both may be utilized. An example of such fiber is that which isreclaimed from the carcass of automotive tires, which a tire cord.

setting resin or binder. better; adhesion between the 'carrierand fillerfibers com third is-of the rubber or elastomerftype.

fibers have been reclaimed therefrom through special re-' claimingmethods, removing the cord from the rubber tire body in a'form known tothe trade as reclaimed Within the fibers composing such cord and on thesurface thereof is to--be found the requisite rubber .for the vproductdescribed without further processing thereof or without addingadditional rubber.

After the carrier and filler fibers have been combined with the elasticmaterial and resinous binder and the composition deposited inthe form ofa mat structure on pointof transfer to a steel flight conveyor, whichpasses through a curing or drying oven of conventional design and'wellknown to the art. Suchoven conveyor has positioned thereabove asecond conveyor also passing through the oven, *the. flights. of whichare in parallel plane to those of the conveyor on which the mat is car-'ried. The oven conveyors are adjustable with respect to each other sothe space between their flights may be varied to govern and control thethickness and density of the-mat. -In other words, by regulating thedistance between the flights of the respective conveyors,,it is possibleto eompressvthe mat structure tovany desired degree during the period itis in a formative state or while in transit through the oven.

i In the oven the mat is'exposed to sufficient heat, when a.thermoplastic binder is used, to cause it to soften and flow. When athermosetting binder is employed, the .heat of the oven is regulated tocure the binder during its. passage .through the oven to a degree thatthe fibers of the mat are bonded intoan integral structure. Methods ofoven drying. and curing thermoplastic and thermosetting binders arewellknown to the art.

In ,order'to produce 'thedesired properties in the resultant compositionor felted mat; it ,is necessary that the elastic material, rubber or anequivalent elastomer',

be used in combination with a thermoplastic or thermo- The product ischaracterized by posing the mat and by a properties a 1 Examples offibers or filaments adaptable as carrier fibersarelong staple cotton,cotton clearer waste. (a form of mill waste obtainedasa waste. materialin clearrnarked increase in its resilient ing .or cleaning cardingmachines in the processing of long staple cotton), rayon, nylon, orother synthetic fiber, filaments, yarns, or threadsjchopped or cut tothedesired length, cottonyarns'-or threads obtained by opening andchopping, cotton garment cloth such as garment r clips or thread wastehaving the requisite length or filamentor thread. This carrier fiber orthread stock is 40 lbs. long staple cottonin the form ct -clearer waste.lbs..powderedphenol formaldehyde resin.

Example 11' I 60 lbs. reclaimed tire cord-as in Examplel.

20 lbs. long staple clearer waste.

20 lbs. of chopped or cut rayon filament or thread stock 1 /2 averagelength.

- 20 lbs. powdered phenol formaldehyde resin;

I g the conveyor belt, t.he mat or felt moves thereon to a characterizedby; lengths ranging predominantly between to 3", although a smallpercentage of shorter materialmay be present, as the necessaryconsequence of methods used' to cut or chopthe fiber to the desired 7lengths;

'Examples' of the filler fiber are cotton linters, cotton napper(recovered from napping operation in the manufacture of cotton'blanketsand the like). and reclaimed tire cord. "The-fill' fiber ischaracterized .by lengths pre dominantly less than ,7

In composing a 'blend or mixture to form the matfa minimum of 25%carrier fiber is used with a maximum of 75% fillfiber and aminimnm of,10% of total binder material by weight isutilized, of'which not les'stha'n one- Fourof themost successful mats or felts are processed fromblends ofethe .recitedmaterials in the'proportions indicated in thefollowing examples: 7 7 V 7 7 Example lbs. of. reclaimed tire .cordhaving a percentage of vulcanized rubber of not less than 10% normorethan 30%, making a composition of to. 90% of cot'ton and 10% to 30%of rubber.

Example 111' 50 lbs. cotton mapper. a V 40'lbs. chopped or cut cotton oring in length from to 3"; 7

l0 lbs-powdered natural or synthetic rubber, -dr.. 1o lbs.

:of rubber solids in the form of a sprayedremulsiont 20 lbs. of vinylchloride acetate resin,-or20 lbs. ofjthc same resin in the form ofsolids in a solution or disperar a 1 V Example If, 50 lbs. cotton napperor cotton'linters.

age length of 1 /2. 20' lbs. phenol formaldehyde resin. '10 lbs.powdered natural or synthetic rubber, 7

- rubber solids in the form of a sprayed emulsion."

30 lbs. glass filament or. glass yarn'chopped to anaver i In theprocessing of the material in the formingisection or hood 'where thefibers, rubber, and binder are combined, andrin the heating'of thematerialin the 'oven,

some part of the binder material contained in the" blend is necessarilylost to the vacuum and in the, form of volatiles which are dischargedthrough the stack.

Typical compositions of finished products contemplated I herein and asmanufactured are asfollows:

,1 racist? Organic fiber '(cotton,'rayon, nylon wool, re.Syntheticiresin (thermoplastic or thermoset- The upper part of the rangeor resin and rubber 'c0n-' tent is utilized in" fiber blendswhichcontain high per:- centages of filler fiber and the lower partof'the'range' of resin and rubber content is used with blendslwhichcontain the higher percentage of carrier fiber.

Thus it will'beseen .that there has been produced a mat or feltedstructureof fibers intimately combined with an elastic material and aresinous .binder;to produce an integral, insulating paid. This mat orpad is bonded into a 7 rugged, resilient composition economicallymanufactured from principally waste material at a low cost anaemtive forinnumerable uses From the foregoing it will be seen that this'inventionfis one well adapted to attain all'of the ,ends' and objec-- L tiveshereinabove set forth, together with ,other advantages which are obviousand which are inherent to the invention. a i a a "It will be understoodthat. certain features 'and sub combinations are of utility and may beemployed without rayon threads to ck or rayon filament of an averagelength of l /2.? and ra ng a 10 lbs.

toinsulate against heat, sound I V and like purposes; J

reference to other features and subcombinations. This is contemplatedby-and is withintheiscopeof the claims.

As many possible embodiments maybe made of the inventionwithout'departingfrom'the.scope thereof, it is to 'be understoodthat'all matter'herein-set forth is to be interpreted asillustrativeand' notina limiting sense.

In the appended'claims' the term rubber-like elastic materialshould'be'understood as meaning materials or mixtures of'materialscharacterized'by the properties of rubberiness and elasticity manifestby'natural rubber; the term thus embraces natural rubber and alsolastics (e. g., synthetic rubber) which are usable in lieu of, or incombination with, natural rubber and exhibit like characteristics whenso used.

Having thus described my invention, I claim:

1. The method of making fibrous mat comprising the steps of mixingcarrier fibers and fill fibers to form a fiber mixture of suchproportions that the fill fibers constitute 50% to 75% of the mixture,the fill fibers being predominantly of a length less than half theaverage length of the carrier fibers, carding said fiber mixture,introducing the carded fibers into an air stream and transporting themsolely by said air stream for an appreciable distance, directing saidair stream through a foraminous barrier to cause the fibers to pile upagainst said barrier in haphazard jackstraw fashion to form a mat, andtranslating said barrier in a direction to carry the mat out of said airstream.

2. The method of making a fibrous mat, comprising the steps of mixingcarrier fibers and fill fibers in such proportions that the latter form50% to 75% of the mixture, the fill fibers being predominantly of alength less than half the average length of the carrier fibers, cardingsaid fiber mixture, introducing the carded fibers into an air stream andtransporting them solely by said air stream for an appreciable distance,introducing particles of a binder material into the same air stream sothey comingle with the fibers as the latter are air-borne thereby, thendirecting said air stream through a foraminous barrier to cause thefibers to pile up against said barrier in haphazard jackstraw fashion toform a mat containing at least part of the binder particles, translatingsaid barrier in a direction to carry the mat out of said air stream, andthen curing the binder contained in said mat to secure the fiberstogether.

3. The method of making fibrous mat, comprising the steps of coatingfibers with a rubber-like elastic material distinct from the fibers,carding the coated fibers, introducing the carded fibers into an airstream and transporting them solely by said air stream for anappreciable distance, introducing particles of a binder material intothe same air stream so they co-mingle with the fibers as the latter areair-borne thereby, then directing said air stream through a foraminousbarrier to cause the fibers to pile up against said barrier in haphazardjackstraw fashion to form a mat which in turn serves to trap at leastpart of the binder particles, translating said barrier in a direction tocarry the mat out of said air stream, and then curing the binder trappedin said mat to secure the fibers together.

4. The method of making fibrous mat comprising the steps of coatingfibers with a rubber-like elastic material distinct from the fibers,mixing uncoated fibers with the coated fibers in such proportions thatthe rubber-like material comprises 3% to by weight of the mixture,carding the fiber mixture, introducing the carded fibers into an airstream and transporting them solely by said air stream for anappreciable distance, introducing a binder into the same air-stream soit co-mingles with the fibers as they are air-borne thereby, thendiverting said air stream through a foraminous barrier to cause thefibers to pile up against said barrier in haphazard jackstraw fashion toform a mat, translating the barrier in a direction to carry the mat outof said air stream, and then curing-the binder 'depositedpoir thefibersin said mat tot: secure the fibers together;

SJThe method of making fibrous matcomprising the steps ofimpregnatingrfibers with a rubber-like elastic material distinct fromthe fibers, mixing the impregnated fibers with unimpregnated fibers insuch proportions that. the'rubber-like material comprises 3% to 20% byweight of the mixture, carding the fiber mixture,'introducing the.carded fibers into an airstream and transporting themsolely by said airstream" for an appreciable distance,

introducing a binder into the same air stream soit comingles with thefibers as they are air-borne thereby, then directing said air streamthrough a foraminous barrier to cause the fibers to pile up against saidbarrier in haphazard jackstraw fashion to form a mat, translating saidbarrier in a direction to carry the mat out of said air stream, and thencuring the binder deposited on the fibers in said mat to secure thefibers together.

6. The method of making fibrous mat comprising the steps of coatingfibers with a rubber-like elastic material distinct from the fibers,mixing said coated fibers with uncoated fibers predominantly of a lengthat least double the average length of the coated fibers, carding saidfiber mixture, introducing the carded fibers into an air stream andtransporting them solely by said air stream for an appreciable distance,introducing a binder into the same air stream so it co-mingles with thefibers as they are airborne thereby, then directing the air streamthrough a. foraminous barrier to cause the fibers to pile up againstsaid barrier in haphazard jackstraw fashion to form a mat, translatingsaid barrier in a direction to carry the mat out of said air stream, andthen curing the binder deposited on the fibers in said mat to secure thefibers together.

7. A method as in claim 6 wherein said coated and uncoated fibers aremixed in such proportions that the latter comprise 25% to 50% of themixture.

8. The method of making fibrous mat comprising the steps of impregnatingfibers with a rubber-like elastic material distinct from the fibers,mixing the impregnated fibers with unimpregnated fibers predominantly ofa length at least double the average length of the impregnated fibers,carding said fiber mixture, introducing the carded fibers into an airstream and transporting them solely by said air stream for anappreciable distance, introducing a binder into the same air stream soit co-miugles with the fibers as they are air-borne thereby, thendirecting said air stream through a foraminous barrier to cause thefibers to pile up against said barrier in haphazard jackstraw fashion toform a mat, translating said barrier in a direction to carry the mat outof said air stream, and then curing the binder deposited on the fibersin said mat to secure the fibers together.

9. The method of making a fibrous mat comprising the steps of mixingcarrier fibers and fill fibers in such proportions that the latter form50% to 75 of the mixture, the fill fibers being predominantly of alength less than half the average length of the carrier fibers, cardingsaid fiber mixture, introducing the carded fibers into an air stream andtransporting them solely by said air stream for an appreciable distance,introducing particles of a binder material and particles of arubber-like elastic material distinct from said binder into said airstream so they co-mingle with the fibers as the latter are air-bornethereby, then directing said air stream through a foraminous barrier tocause the fibers to pile up against said barrier in haphazard jackstrawfashion to form a mat, translating said barrier in a direction to carrythe mat out of said air stream, and then curing the binder deposited insaid mat by the air stream to secure the fibers and particles ofrubber-like elastic material together.

10. The method of making a fibrous mat comprising the steps of cardingthe fibers, introducing the carded fibers into an air stream andtransporting them solely by said air stream for an appreciable distance,introducing areas-5mg 'bysth e ai:r stream;;thei1'directifig said airstream'through a'foraminous' barrier to cause the fibers tqpileupl-agaiiist said barrier in haphazard jackstraw fashion to form a-matwhichserves in turn to trap at least part of said particles, translatingsaid barrier in-a direc tion to carry the mat out of said air stream,and then ciiring the binder trapped insaid mat tosecure together thefibers and particles of rubber-like elastic material;

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